The present disclosure relates to methods of making nanostructured materials. In particular, embodiments herein related to methods of making metal nanostructured materials as exemplified by the preparation of silver nanodendrimer structures.
The design and fabrication of metal nanostructures that are tunable to adapt to numerous downstream applications related to sensors, solar cells, nanoelectric devices, biomedical and imaging processes is of increasing importance. Depending on the size and shape of nanostructured metal, electronic, photonic, optical, magnetic and catalytic properties can be fine-tuned for the appropriate application. Some common nanostructured morphologies include nanoparticles, nanorods and nanowires. More complicated nanostructures include multi-branched hierarchical-type nanostructures which are being employed increasingly in biosensor devices, photovoltaics and nanoelectronics. Other areas of interest include environmental chemistry and device fabrication and materials design. By applying a “bottom-up approach” used in nanomaterial chemistry, materials can be designed and systematized at the nanometer scale.
The fabrication of these higher organized nanostructures, such as nanotrees and nanodendrites, generally requires high temperatures and rather harsh reaction conditions. FIG. 1 shows an exemplary process for the growth of silver dendrites on silicon wafer. One approach to forming metallic dendrites is by electrochemical deposition onto electrode surfaces. Other methods include hydrothermal synthesis, chemical vapor deposition, photolithography-assisted wafer scale fabrication, liquid phase reduction, solvothermal, ultraviolet irradiation photoreduction and other electrochemical methods. FIG. 2 shows numerous dendrite morphologies that may be accessed by the aforementioned methods.
However, there is a continuing need to develop methods to create these hierarchical structures via simple and cost-effective and environmentally sound ways for large scale applications. The methods described herein provide these and other advantages.